The present disclosure relates to a communication device.
Recently, communication devices capable of communicating with a reader/writer (or a communication device having a reader/writer function, hereinafter, the same) in a non-contact manner have come into wide use, for example, mobile phones provided with a non-contact IC (Integrated Circuit) card, an RFID (Radio Frequency Identification) tag, and a non-contact IC chip.
The communication device such as the reader/writer, the IC card, and the mobile phone uses magnetic field (carrier wave) of a specific frequency such as 13.56 MHz in communication. Specifically, the reader/writer transmits the carrier wave carrying with a transmission signal, and the communication device receiving the carrier wave by an antenna answers a response signal for the received transmission signal by load modulation, thereby performing communication between the reader/writer and the communication device.
The communication between the reader/writer and the communication device is internationally standardized as, for example, ISO 18092 standard (NFC (Near Field Communication) standard), and services using the non-contact communication described above are provided around the world.
In this context, a technique of achieving stabilization of communication has been developed. For example, there are techniques disclosed in Japanese Unexamined Patent Application Publication No. 2008-17012 and Japanese Unexamined Patent Application Publication No. 2009-272697 for preventing a phenomenon (so-called “null points”) in which it is not possible to perform communication normally, where there are points at certain distances in which the non-contact communication can be difficult to perform.